294 



COMPARATIVE ANATOMY 



CHAP. 



FIG. L'36. Schizaster lacu- 

 nosus ? from the apical side 

 (original). The spines, and the 

 protuberances on which they 

 stand, are not depicted. 1, The 

 anterior unpaired ambulacrum ; 



2, the right anterior ambulacrum ; 



3, fascicle ; 4, the right posterior 

 interambulacrum ; 5, the right 

 posterior ambulacrum ; 6, the 

 unpaired posterior interambula- 

 crum ; 7, anal region. 



Fio. 237. Palaeopneustes 

 Murray! (after Agassiz), 

 from the oral side. 1, The 

 anterior ambulacrum ; 2, 3. 

 the anterior right and the 

 posterior right ambulacra : 

 4, peristome ; 5, anal region. 



